The present invention relates to machine tools of the type having a frame with a tool holding recess in the bed, and more specifically, to a method and apparatus for effecting alignment and movement of a die in a precise attitudinal position in registry with the tool holding recess.
A number of machine tools employ cooperating tooling in the head and bed of the machine frame; punch presses and nibbling machines are notable examples. In such machines, the punch is typically inserted horizontally into a tool holder in the upper frame, and that holder has a recess for receiving and aligning it. The bottom tool or die must be moved over the die holder in the bottom of the frame of the machine and then pushed downwardly into a recess in the bed. In order to guarantee precise and firm seating of the die in the die holder, there must be a close fit between the abutting surfaces of the die and the recess of the die holder in which it is seated.
The peripheral contours of the die and the cooperating recess in which it is seated are frequently circular, but the circular configuration can be interrupted by projecting portions and recesses. However, the cross-section of the recess in which the die is seated generally must remain constant from its open upper end to its bottom wall; a bevel or chamfer will not normally be utilized because the upper surface of the die must be flush with the surface of the die holder thereabout to support the sheet metal or other workpiece. As a result, the need for a close fitting relationship between the periphery of the die and the recess and the die holder makes insertion of the die into the die holder quite difficult because even a slight deviation from a perfectly horizontal attitude will make its movement downwardly thereinto almost impossible.
As is well known, the die holder in the frame will also have an opening in its bottom wall for discharge of scrap and the like. Although it is common for the die holder to be a separate element supported on the machine frame, it can be fabricated as a part of the bed of the frame, and the term "tool holder" as used herein contemplates a separate tool holder providing the tool-receiving recess or merely a portion of the frame doing so.
It is an object of the present invention to provide a novel machine tool operation in which a die or like tooling can be positively oriented and guided downwardly into a cooperating recess in the machine frame.
It is also an object to provide such a method in which the die or like tooling is precluded from rotation upon seating in the cooperating recess in the machine bed.
Another object is to provide a unique machine tool assembly wherein the die may be precisely oriented in the desired horizontal attitude and moved readily into position within a cooperating die recess in the machine bed.
Still another object is to provide such a machine tool wherein the die and die receiving element may be readily fabricated, and are of rugged and durable construction.